Final answer:
A refractometer does not perform an abdominal fluid pH test. It measures the specific gravity of urine and the total protein concentration in body fluids like abdominal fluid and plasma, but pH testing needs different equipment.
Step-by-step explanation:
The test that is not performed using a refractometer is abdominal fluid pH. A refractometer is commonly used in medical testing to measure the specific gravity of urine, which is the ratio of the density of the urine to the density of water. It is a quick way to assess kidney function, as the kidneys must concentrate urine by reabsorbing water, a process that affects its specific gravity. Additionally, refractometers can determine the total protein concentration in various body fluids such as abdominal fluid and plasma, which can be valuable in diagnosing conditions or checking the body's protein status. However, measuring pH is not a function of refractometry; pH testing requires different methods and equipment, such as pH meters or strips, because it evaluates the acidity or alkalinity of a solution rather than its refractive index, which is what a refractometer measures.